Technical innovation, lightening and thinning, and functionalization of mobile terminals and portable electronic products impose a higher requirement for energy density of batteries. However, an increase speed of the energy density of the batteries seriously lags behind needs for the energy density of the batteries and a gap between supply and demand of energy is increasingly widened. This is macroscopically manifested by a short service time of electronic products, which seriously restricts performance of the electronic products and results in poor experience of consumers. A solar battery technology that converts natural light energy into electric energy is a possible method for resolving insufficiency of energy supply. A solar battery generates electricity under a lighting condition, which can not only directly provide electric energy to an electronic product, but also charge a battery equipped in the electronic product in order to prolong a service time of the electronic product.
From a perspective of appearance, a solar battery may be in a tablet, flexible thin-film, or filamentous form. A tablet solar battery is mainly applicable to a centralized or distributed large-scale electricity generation scenario, a flexible thin-film solar battery is applicable to electricity supply for integrated buildings, flexible electronic devices, and wearable electronic devices (such as intelligent watches and glasses), and a filamentous solar battery has a small volume and can be bent into any shape, and therefore is more suitable for integration with an electricity-using product and is highly portable. In addition, the filamentous solar battery may be woven into cloth for making clothes or flexible thin-film batteries in order to be applied to fields to which a thin-film battery and a tablet battery are applicable. In comparison, the filamentous solar battery has wider application scenarios, and is an ideal form of the solar battery.
The solar battery is an electric energy generation apparatus. Carriers generated by a photoelectric active material inside the solar battery are separately conducted through two electrodes to form a current using an external circuit in order to complete an electricity generation process. Therefore, at present, during an application, the solar battery needs to be externally connected to an energy storage apparatus (such as a lithium-ion battery and a lead-acid battery) for storing electric energy. This is true with, for example, current centralized electricity generation from solar energy and charging a mobile phone using a solar earphone. In order to implement a concept of supplementing electric energy using light energy, two components a solar battery and an energy storage battery are needed, which results in two deficiencies. Firstly, the solar battery cannot be applied independently. If there is no energy storage device, the solar battery cannot implement electricity generation even if there is strong light irradiation, thereby wasting resources. Secondly, the solar battery and the energy storage battery need to be connected using an external wire. Therefore, for mobile application scenarios such as intelligent terminals and portable electronic products, a solar battery device and an electronic product need to be connected all the time using a wire, which brings lots of inconvenience to daily life of consumers.